In this essay, I sketch a critical analysis of doctrines and practices commonly identified as instances of “preventive justice.” In Part I, after rehearsing briefly the distinction between law and police as alternative modes of governance best viewed in contradistinction to one another, I argue that preventive justice is neither new, nor different, being instead a long familiar instance of penal police. Part II moves from analysis to critique, considering briefly various criticisms of “preventive justice” raised, or implied, and concluding that they miss the mark, either because they are inapposite (from the perspective of police) or unfounded (from the perspective of law).